Heater Circuit Inspection

Check Power to HO2S Heater

1. Ignition "ON" & Engine "OFF"
2. Disconnect HO2S connector.
3. Measure voltage between terminal "3" of the HO2S harness connector and chassis ground.
   1. Specification: Approx. B+
      Fig 1: Measuring Voltage Between Terminal 3 Of HO2S Harness Connector And Chassis Ground

      
4. Is the voltage within specifications?

   YES

   1. Go to "CHECK FOR OPEN IN HARNESS" as below.

   NO

   1. Check for open in Heater power harness. Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.

Check for Open in Harness

1. Ignition "OFF".
2. Disconnect HO2S connector and PCM connector.
3. Measure resistance between terminal "4" of the HO2S harness connector and terminal "A4" of the PCM harness connector.
   1. Specification: Prix. 0Ω.
      Fig 2: Measuring Resistance Between Terminal 4 Of HO2S And Terminal A4 Of PCM Harness Connector

      
4. Is the resistance within specifications?

   YES

   1. Go to "SYSTEM INSPECTION " procedure.

   NO

   1. Check for open in Heater control harness. Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.